Fears over reaction to damning report into child grooming which shows one in five of those accused is Asian

Vulnerable: More than 2,000 young people, most of them young girls, have been groomed for sex by British gangs in the last three years, but experts say that this figure is the 'tip of an iceberg'

One in five men accused of grooming underage girls for sex is Asian, according to a damning report.

It found that many more British children 'than thought' are falling into the clutches of sexual predators because they are not being adequately protected by the authorities.

The thousands of known victims who were groomed for sex by adults in the past three years are believed to be the 'tip of an iceberg', experts have warned.

Authorities are failing properly to investigate the problem, which the Child Exploitation and Online Protection Centre (Ceop) has described as a 'hidden issue' in British society.

The information on child grooming is so inaccurate that in almost 40 per cent of cases the ethnicity of the perpetrator is not known.

However there are fears the report could provoke a row about ethnicity despite it being expected to say that the problem cannot be associated with a particular ethnic group. There was anxiety within the civil service about how to 'present' the publication, due to be released next week.

Keith Vaz, chairman of the Commons Home Affairs Select Committee, said that much more work needed to be carried out to find out the scale of grooming across the country.

'The findings are a cause for enormous concern because it appears to be a much larger issue than originally imagined,' he said.

He warned against stigmatising particular communities but said: 'If indeed it requires upsetting groups or individuals, it just has to be done.'

More than 2,000 young victims of grooming have been identified since January 2008 - but they are likely to form just a fraction of the total number affected, the report is expected to reveal.

The report comes after the ringleaders of a gang which subjected a string of vulnerable girls to rapes and sexual assaults were jailed indefinitely earlier this year.

Abid Saddique and Mohammed Liaqat, who were each married with a child, cruised the streets of Derby in a car for victims while their unsuspecting families waited at home for them.

The vulnerable children were plied with vodka stored under the seats and taken to parks, hotel rooms or houses, where they were sometimes offered cocaine before being pressured into sex.

Some of the victims were runaways, and Ceop has found that missing children or those who run away from home are the most susceptible to grooming.

Jailed: Abid Mohammed Saddique (left) and Mohammed Romaan Liaqat (right), were ringleaders of a gang which ensnared children and committed a catalogue of sexual offences against vulnerable young girls

Peter Davies, Ceop's chief executive, launched the investigation into grooming within local communities after former home secretary Jack Straw accused some Pakistani men in Britain of seeing white girls as 'easy meat' for sexual abuse.

In January, Mr Straw said child sex grooming was a 'specific problem' in the Pakistani community which needed to be 'more open' about the reasons behind it.

Speaking at the time, Mr Davies said: 'Child sexual exploitation is not exclusive to any single culture, community, race or religion - it cuts across all communities.

CCTV footage showed Mohammed Romaan Liaqat and Abid Mohammed Saddique cruising the streets of Derby in a BMW trying to pick up vulnerable children to exploit them

'Neither can it be simplified along ethnic lines where the victims constitute one ethnicity and offenders another.

'We need to continue to build our understanding about the different types of threats faced by children across a range of environments.'

Children's charity Barnardo's, Muslim youth group The Ramadhan Foundation and retired detective chief superintendent Max McLean, who led a previous investigation into sexual exploitation involving young girls in Leeds, all said Mr Straw was wrong to highlight one community.

Frightening: Keith Vaz MP (left) says the issue of the sexual grooming of children in the UK is clearly 'much larger than imagined' while Ann Coffey MP (right) says that police and other authorities must do more to track missing children

New figures show that 842 of the 2,083 victims since 2008 ran away from home or a council-run children's home, for example.

Ann Coffey, the Labour chairman of the all-part parliamentary committee on runaway and missing children said: 'What is clear is that children are being trafficked across local police force borders, from flat to flat, for sex. Sometimes it is only for a short period but it is happening.

'Some of these children are from care homes and that is particularly disappointing as they are people we, the state, have taken into care because they are at risk and then they suffer this.'

Tomorrow she will start a debate in the Commons about the link between runaways and sexual exploitation of children.

In particular she will highlight how numbers of missing children are not recorded well enough, with councils not having to report children missing until after 24 hours and others failing to do so at all.

The Government's Children's Minister Tim Loughton and Crime Minister James Brokenshire are preparing an action plan because of increasing concerns about the sexual grooming and trafficking of British children.

Key to this will be the improved recording of these crimes and keeping better track of missing children.